WFC3 Infrared Spectroscopic Parallel (WISP) survey: photometric and emission-line data release

Abstract

International audienceWe present reduced images and catalogues of photometric and emission-line data (∼230 000 and ∼8000 sources, respectively) for the WFC3 (Wide Field Camera 3) Infrared Spectroscopic Parallel (WISP) survey. These data are made publicly available on the Mikulski Archive for Space Telescopes and include reduced images from various facilities: ground-based ugri, Hubble Space Telescope (HST) WFC3, and Spitzer IRAC (Infrared Array Camera). Coverage in at least one additional filter beyond the WFC3/IR data are available for roughly half of the fields (227 out of 483), with ∼20 per cent (86) having coverage in six or more filters from u band to IRAC 3.6 |$\mu$|m (0.35–3.6 |$\mu$|m). For the lower spatial resolution (and shallower) ground-based and IRAC data, we perform PSF (point spread function)-matched, prior-based, deconfusion photometry (i.e. forced-photometry) using the tphot software to optimally extract measurements or upper limits. We present the methodology and software used for the WISP emission-line detection and visual inspection. The former adopts a continuous wavelet transformation that significantly reduces the number of spurious sources as candidates before the visual inspection stage. We combine both WISP catalogues and perform spectral energy distribution fitting on galaxies with reliable spectroscopic redshifts and multiband photometry to measure their stellar masses. We stack WISP spectra as functions of stellar mass and redshift and measure average emission-line fluxes and ratios. We find that WISP emission-line sources are typically ‘normal’ star-forming galaxies based on the mass–excitation diagram ([O iii]/Hβ versus M_⋆; 0.74 < z_grism < 2.31), the galaxy main sequence (SFR versus M_⋆; 0.30 < z_grism < 1.45), S_32 ratio versus M_⋆ (0.30 < z_grism < 0.73), and O_32 and R_23 ratios versus M_⋆ (1.27 < z_grism < 1.45)